package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import javax.management.Query;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;
    @Override
    public Result queryHotBlog(Integer current) {
        //根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        //获取当前页面的数据
        List<Blog> records = page.getRecords();
        //查询用户
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result queryBlogById(Long id) {
        //1.查询单个博客
        Blog blog = getById(id);
        if(blog==null){
            return Result.fail("笔记不存在");
        }
        //2.查询blog有关的用户
        queryBlogUser(blog);
        //3.查询blog是否被点赞
        //4.查询Redis set集合中是否有单前用户的id
        isBlogLiked(blog);
        //5.如果存在则件isLike改为 true
        return Result.ok(blog);
    }
    //判断用户是否被点赞
    private void isBlogLiked(Blog  blog) {
        //1.获取当前用户
        UserDTO user = UserHolder.getUser();
        if(user==null){
            //用户未登录，无法查询是否点赞
            return;
        }
        Long userId = user.getId();
        //2.判断是否点赞
        String key = "blog:liked:" + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //3.设置是否被点赞过了
       blog.setIsLike(score != null);
    }

    @Override
    public Result likeBlog(Long id) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2.判断是否点赞
        String key = BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        //如果 score 为 null ，则返回 true。
        //如果 score 的值为 true，则返回 false。
        if(score== null){
            //3.如果未点赞，可以点赞
            //3.1 修改数据库的数据，点赞数加一
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            if(isSuccess){
                //3.3 添加到redis的score set集合中，保存所有点赞的id zadd key value score
                stringRedisTemplate.opsForZSet().add(key, userId.toString(), System.currentTimeMillis());
            }else {
                //如果点赞失败
                return Result.fail("点赞失败");
            }
        }else {
            //4.如果点过赞了，可以取消点赞
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            if(isSuccess){
                //4.1 移除用户
                stringRedisTemplate.opsForZSet().remove(key, userId.toString());
            }else {
                //如果取消点赞失败
                return Result.fail("取消点赞失败");
            }
        }
        return Result.ok();
    }
    //实现点赞排行榜
    @Override
    public Result queryBlogByLikes(Long id) {
        //1.查询Redis中的zset中排序为前五的数据
        String key = BLOG_LIKED_KEY + id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5==null||top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        //2.解析出其中的用户ID数据
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        //3.根据用户ID去查询用户数据
        List<UserDTO> userDTOS = userService.query().in("id", ids)
                .last("ORDER BY FIELD(id,"+idStr+")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        //4.返回
        return Result.ok(userDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
        //1.获取当前登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        //2.保存探店博文
        boolean isSuccess = save(blog);
        if(!isSuccess){
            return Result.fail("新增笔记失败");
        }
        //3.查询笔记作者的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", blog.getUserId()).list();
        //4.推送笔记给所有粉丝
        for (Follow follow : follows){
            //4.1获取粉丝id
            Long userId = follow.getUserId();
            //4.2推送
            //每一粉丝都应该有一个自己的feed流Zset,实现关注的用户，推送笔记到粉丝的收件箱当中
            String key = FEED_KEY + userId;
            stringRedisTemplate.opsForZSet().add(key, blog.getId().toString(), System.currentTimeMillis());
        }
        //3.返回ID
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1.获取当前用户
        Long id = UserHolder.getUser().getId();
        //2.查询收件箱
        String key = FEED_KEY + id;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        //3.非空判断
        if(typedTuples==null||typedTuples.isEmpty())
        {
             return Result.ok();
        }
        //创建一个集合，用来收集博客id
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime=0;
        int os=1;
        //4.解析数据：blogId,minTime(时间戳)，offset（相同元素的个数）
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples){
            //4.1获取id
            ids.add(Long.valueOf(tuple.getValue()));
            //4.2获取分数score（时间戳）
            long time = tuple.getScore().longValue();
            if(time==minTime){
                os++;
            }else{
                minTime =time;
                os=1;
            }
        }

        //5.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();

        for (Blog blog : blogs) {
            //5.1查询blog有关的用户
            queryBlogUser(blog);
            //5.2查询blog是否被点赞
            isBlogLiked( blog);
        }
        //6.封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);

        return Result.ok(r);
    }

    //
    private void queryBlogUser(Blog blog) {
        //获取当前用户的的用户id
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        if (user != null) {
            blog.setName(user.getNickName());
            blog.setIcon(user.getIcon());
        }
    }
}
